1. Field of the Invention
The present invention relates to a control device for controlling the voltage generated by a vehicle alternating current generator and the vehicle alternating current generator that supplies power to an electrical load such as a battery using the control device mounted on a vehicle.
2. Description of the Related Art
FIG. 6 is a lateral cross-sectional view of a conventional vehicle alternating-current generator 1. FIG. 7 is a cross-sectional view showing the major portion of the vehicle alternating current generator of FIG. 6. A bracket 2 is constructed by connecting a front bracket 2a to a rear bracket 2b by bolts 3. Disposed along the inner wall of the bracket 2 is a stator 5 made up of stator cores 6 around which stator windings 7 are wrapped. An axis of rotation 8 is inserted along the center line of the bracket 2. The axis of rotation 8 is rotatably supported at its both ends by bearing 9. An exciting core 10 having an unshown exciting coil is attached to the middle portion of the axis of rotation 8.
Disposed on the inside of the front bracket 2a is a control device 11 for controlling the voltage generated by the alternating-current generator 1. A pair of brushes 13 is mounted within the holder 12 of the control device 11. Springs 14 urge the brushes 13 so that the brushes 13 are slidably in contact with slip rings 15 attached onto the axis of rotation 8 at a predetermined pressure. A rectifier device 16 that rectifies the alternating current from the stator windings 7 into a direct current is mounted opposite the control device 11, diagonally across the axis of rotation 8. Disposed next to the rectifier unit 16 is an auxiliary rectifier unit 17 for feeding a current to the exciting coil.
FIG. 8 is a front view showing the control device 11 only of FIG. 7. FIG. 9 is a view of the control device 11 viewed vertically from above in FIG. 8 as shown by the arrow B. FIG. 10. is a view of the control device 11 viewed horizontally from the side in FIG. 8 as shown by the arrow A. FIG. 11 is a cross-sectional view of the control device 11 of FIG. 8, taken along the line C--C. FIG. 12 shows the major portion of FIG. 10.
A connector 18 for external connection is integrally attached onto the holder 12. The holder 12 has a ceramic substrate 19 layered on top of a heat sink 24. The ceramic substrate 19 has a hybrid IC 21 containing electrical components and an IC for controlling the voltage generated by the vehicle alternating-current generator. FIG. 13 shows the circuit configuration of the hybrid IC 21, the main component of the control unit, which will be described in detail later. The holder 12 has a silicone resin filler 22 that protects the voltage regulating hybrid IC 21 against moisture and dust. First leads 23a of the hybrid IC 21 vertically extend from one end of the substrate 19 and second leads 23b vertically extend from the other end of the substrate 19. The ends of the first leads 23a are connected to first conductor links 70a leading to the main unit of the alternating-current generator. The ends of the second leads 23b are connected to second conductor links 70b that are in turn connected to a battery (not shown). The conductor links 70a, 70b are produced by press-cutting a thin steel sheet, and then insert-molded in the holder 12.
FIG. 13 is the schematic diagram of the alternating-current generator 1 mounted on a vehicle. The main unit 100 of the alternating-current generator houses three-phase star-connected armature coils 101 and an exciting coil 102. The full-wave rectifier 200 connected to the main unit 100 of the alternating-current generator has an rectifier output terminal 201, a ground terminal 202, input terminals 203 that are connected to the ends of the armature coils 101, and diodes connected between the input terminals 203 and the output terminal 201, and diodes connected between the input terminals 203 and the ground terminal 202. The voltage regulating section 300 connected to the full-wave rectifier 200 comprises voltage dividing resistors 301, 302, a zener diode 303, the cathode of which is connected to the junction of the resistors 301 and 302, a control transistor 304, the base of which is connected to the anode of the zener diode 303, and the emitter of which is grounded, a base current supplying resistor 305, one end of which is connected the collector of the control transistor 304, a switching element such as an emitter-grounded power transistor 306, the base of which is connected to the collector of the control transistor 304 and the collector of which is connected to the rectifier output terminal 201 of the rectifier 200 via the exciting coil 102 of the main unit 100 of the alternating-current generator, and a suppressing diode 307 connected between the rectifier output terminal 201 and the collector of the power transistor 306 with its anode to the terminal 201.
A battery 400 is connected between the rectifier output terminal 201 of the full-wave rectifier 200 and ground. A key switch 500 is connected between the positive terminal of the batter 400 and the other end of the base current supplying resistor 305 in the voltage regulating section 300. A detector/controller section 600 is connected between the voltage regulating section 300 and the key switch 500. The detector/controller section 600 comprises a smoothing resistor 601, one end of which is connected to one of the input terminals 203 of the full-wave rectifier 200, namely connected to one of the armature coils 101 of the main device of the alternating-current generator 100, a backward current componenting diode 602, the anode of which is connected to the other end of the smoothing resistor 601, a smoothing capacitor 603 connected between the cathode of the backward current componenting diode 602 and ground, a smoothing resistor 604, one end of which is connected to the cathode of the backward current componenting diode 602, and a control transistor 605, the base of which is connected to the other end of the smoothing resistor 604 and the emitter of which is at ground. The detector/controller section 600 further comprises a base current supplying resistor 606 connected between the controller of the control transistor 605 and the key switch 500, and a switching element such as a power transistor 607, the base of which is connected to the collector of the control transistor 605 and the emitter of which is at ground. An indicator lamp 700 is connected between the power transistor 605 and the key switch 500.
At the moment the key switch 500 is switched on in the vehicle alternating-current generator 1, the generator main unit 100 does not start generating yet. A generation signal to be described later is not yet fed to the detector/controller section 600, and thus the control transistor 605 remains nonconductive. When the key switch 500 is switched on, however, the battery 400 is connected to the power transistor 607 via the base current supplying transistor 606 allowing a current to flow through the base of the power transistor 607. The power transistor 607 thus becomes conductive, causing the indicator lamp 700 to light to indicate that the generator main unit 100 is in a generation inoperative state.
The voltage of the battery 400 is high enough to cause the zener diode 303 in the voltage regulating section 300 to conduct when the key switch 500 is switched on. The control transistor 304 remains nonconductive. A current flows through the base of the power transistor 607 from the battery 400 via the base current supplying resistor 305, causing the power transistor 607 to conduct and thereby causing an exciting current to flow through the exciting coil 102.
When the exciting coil 102 is driven by the exciting current, the generator main unit 100 starts generating current. The armature coils 101 give a generation signal to the detector/controller section 600. The output voltage of the generator main unit 100 rises. Upon receiving the generation signal, the control transistor 605 in the detector/controller section 600 becomes conductive, causing the power transistor 607 to cut off. The indicator lamp 700 goes off, indicating that the generator main unit 100 is now generating current.
When the output voltage of the generator main unit 100 is lower than a predetermined value, both the zener diode 303 and the control transistor 304 remain nonconductive while the power transistor 306 remains continuously conductive. As a result, the exciting current flowing through the exciting coil 102 increases, causing the output voltage of the generator main unit 100 to rise even further. When the output voltage rises above the predetermined value, both the zener diode 303 and control transistor 304 become conductive, causing the power transistor 306 to cut off. The exciting current flowing through the exciting coil 102 decreases, resulting in a decreased output voltage. The above operation is repeated so that the output voltage of the generator is controlled to the predetermined value by means of the voltage regulating section 300.
In the control device of the vehicle alternating-current generator thus constructed, conductor links 70a, 70b in the holder 12 are arranged in two rows, one on the left-hand and the other on the right-hand sides, so that connection with the exciting coil 102 and the battery 400 is facilitated. The control component for regulating the generated voltage comprises HIC 21 formed of the ceramic substrate 19 on which electronic components are mounted as shown in FIGS. 11 and 12, first four leads 23a (designated letters d, e, f and g in FIG. 13) on one side, and second three leads 23b (designated letters a, b, and c in FIG. 13) on the other side mounted in the holder 12.
Since the control component of an open type such as HIC 21 with exposed electronic components is flexible enough to accommodate specification change, it is advantageously applied for use in non-standard or semi-standard specification control device. Since electronic components are exposed, care must be exercised while the control component is in the course of placement and mounting on the holder 12. Furthermore, automated mounting of the control component is difficult.
The control component having a standardized specification, as a standardized control component, may be constructed of a control component in a molded package, with a view to resolving the above problem and facilitating automated mounting process.
An open-type control component may be applied for use in non-standard specification or semi-standard specification control component, and a molded-package type control component may be applied for use in standard specification control component. When a molded-package-type control component is manufactured, it is a typical practice to adopt a single in-line molded package design with its leads arranged on a single side from the standpoint of easy mounting onto a substrate and space saving.
The open-type control component has the first and second leads 23a, 23b in two separate rows, one on the left-hand side and the other on the right-hand side. In the single in-line molded package type control component, the leads are arranged on a single row on a single side, and a holder must be so designed that its conductor links are aligned with their associated leads. Thus, two types of holder 12 are required, one for accommodating the open-type control component and the other for accommodating the single in-line molded package type control component.